Simple masking shader for VVVV

gistfile1.cpp

//@author: alg (Vadim Smakhtin)
//@help: masking with binary image. Black - alpha, white - visible.
//@tags: mask, alpha
//@credits:

// --------------------------------------------------------------------------------------------------
// PARAMETERS:
// --------------------------------------------------------------------------------------------------

//transforms
float4x4 tW: WORLD;
float4x4 tV: VIEW;
float4x4 tP: PROJECTION;
float4x4 tWVP: WORLDVIEWPROJECTION;

//material properties
float4 cAmb : COLOR <String uiname="Color";>  = {1, 1, 1, 1};
float Alpha = 1;

//texture
texture Tex <string uiname="Texture";>;
sampler Samp = sampler_state
{
    Texture   = (Tex);
    MipFilter = LINEAR;
    MinFilter = LINEAR;
    MagFilter = LINEAR;
};

texture MaskTex <string uiname="Mask";>;
sampler MaskSamp = sampler_state
{
    Texture   = (MaskTex);       
    MipFilter = LINEAR;
    MinFilter = LINEAR;
    MagFilter = LINEAR;
};

float4x4 tTex: TEXTUREMATRIX <string uiname="Texture Transform";>;

struct vs2ps
{
    float4 Pos : POSITION;
    float4 TexCd : TEXCOORD0;
	float4 MaskTexCd : TEXCOORD1;
};

// --------------------------------------------------------------------------------------------------
// VERTEXSHADERS
// --------------------------------------------------------------------------------------------------

vs2ps VS(
    float4 Pos : POSITION,
    float4 TexCd : TEXCOORD0)
{
    vs2ps Out = (vs2ps)0;

    Out.Pos = mul(Pos, tWVP);

    Out.TexCd = mul(TexCd, tTex);
	Out.MaskTexCd = TexCd;

    return Out;
}

// --------------------------------------------------------------------------------------------------
// PIXELSHADERS:
// --------------------------------------------------------------------------------------------------

float4 PS(vs2ps In): COLOR
{
    float4 col = tex2D(Samp, In.TexCd) * cAmb;
	float maskCol = tex2D(MaskSamp, In.MaskTexCd);
	
    col.a = maskCol > 0;
    return col;
}

// --------------------------------------------------------------------------------------------------
// TECHNIQUES:
// --------------------------------------------------------------------------------------------------

technique TConstant
{
    pass P0
    {
        VertexShader = compile vs_3_0 VS();
        PixelShader = compile ps_3_0 PS();
    }
}